According to recent enhancement of a cold storage industry, frozen and chilled foods should be observed, and in particular, foods such as milk products, fishes and fruits in dietary life should be always maintained in a fresh state throughout the entire distribution process from producers to consumers. However, consumer in a last consumer distribution phase cannot discriminate whether foods are appropriately stored throughout the entire distribution process but can merely determine whether the foods are in a chilled state during a purchase step.
In addition, a manager who professionally manages distribution of foods could not easily recognize frequently whether the corresponding foods are distributed in a safe cold storage stage. While a plurality of methods and apparatuses for recognizing the frozen and chilled state are disclosed, such conventional methods and apparatuses cannot determine whether the safe cold storage state is maintained throughout the entire distribution process.
Reviewing the conventional art, there is a food container having a display section showing a proper storage state corresponding to a frozen or chilled state. The food container uses a film type thermometer attached to an upper surface of a cover of the food container, in which foods are contained and chilled in a refrigerator, and configured to change its color according to a variation in temperature, enabling discrimination of a proper cold storage state of contents through a mark.
In addition, as a similar technique, a temperature display device including a “label” structure having a temperature display function and configured to visually and noticeably display various colors according to a temperature change is disclosed.
That is, as can be seen from an exploded perspective view of a conventional temperature indicator of FIG. 1, the temperature indicator is a product named “Monitor Mark” of 3M, which is commercially available. A temperature indicator 10 includes a developing material layer 11 configured to enable diffusion through reaction at a set temperature or more, and a developing medium layer 12 configured to absorb a solvent from the developing material layer 11. The developing material layer 11 is a temperature sensor layer formed of ink, fatty acid, paraffin, or the like, and the developing medium layer 12 is formed of a blotting paper or non-woven fabric. A blocking layer 13 is disposed between the developing material layer 11 and the developing medium layer 12. A support layer 14 and a double-sided adhesive tape 15 are disposed under the developing material layer 11. A display layer 16 having a display window is formed on the developing medium layer 12. The display layer 16 has a slightly large display window 16′ and slightly small several display windows 16″ formed at a position of the developing medium layer 12 in a longitudinal direction thereof. A transparent coating layer 17 is disposed on the display layer 16.
Meanwhile, the developing medium layer 12, the display layer 16 and the transparent coating layer 17 have cutting sections 18 disposed at the same position of one sides thereof and having the same size. The cutting sections 18 are attached to each other by applying an adhesive agent to lower sections thereof. The display layer 16 is disposed on the blocking layer 13 in a state in which the display windows 16′ and 16″ are disposed on the developing medium layer 13, and the transparent coating layer 17 is disposed on the display layer 16, assembling the temperature indicator.
Accordingly, the temperature indicator 10 is connected to the chilled product by applying an adhesive agent to a bottom surface of the double-sided adhesive tape 15 to attach the tape to the chilled product, removing the cutting section 18 and extracting the blocking layer 13, and attaching the developing material layer 11 to the developing medium layer 12. Next, in the temperature indicator, the developing material layer 11 is actuated due to an increase in ambient temperature so that the ink, fatty acid or paraffin having pigment is melted to permeate the developing medium layer 12, and a storage state of the product is displayed through the display windows 16′ and 16″.
However, the developing material the temperature indicator 10 is actuated on the developing medium layer in the longitudinal direction, the product size is increased, the blocking layer between the developing medium layer and the developing material layer should be carefully removed upon use, and automation for mass production cannot be easily realized.
In addition, since the developing material of the temperature indicator 10 is not sealed but exposed, the developing material should be cooled for 1 to 2 hours before use. If the developing material is used in a state carelessly exposed to a normal temperature, the developing material may be melted to be stuck to the blocking paper upon removal thereof.
In particular, since a developing speed of such a strip type is reduced as it goes away from a starting point when the developing material develops in one direction, a mechanical error range with respect to confirmation of a critical temperature exposure time may be increased.
In addition, as another typical example in a conventional art, a time indicator and a manufacturing method thereof are disclosed in U.S. Pat. No. 7,232,253 (Jun. 19, 2007). The time indicator includes a first storage room, and an actuation unit configured to come a moving medium in contact with a liquid to convey them to the first storage room such that the liquid after actuation moves via the moving medium in which a color change occurs. The actuation unit includes a second storage room connected between the first storage room and the moving medium. Accordingly, the liquid after actuation is moved from the first storage room to the second storage room at a relatively high speed, and then, moved in a length of the moving medium at a relatively low speed.
While the time indicator of US Patent visually displays the product lifespan, since the liquid, which becomes the developing material upon actuation, is moved to a liquid conduit and then come in contact with the moving medium to be actuated in the longitudinal direction, a moving path of the liquid is bifurcated to make it impossible to accurately measure the time lapse. In addition, since a liquid sealing section is installed to block the liquid conduit to actuate and destruct an actuation unit (a dish-shaped section), which becomes the first storage section, with a certain force, the liquid sealing section may be destructed frequently due to carelessness when the moving medium is actuated to the first storage room by the actuation unit, and the liquid is leaked to the outside. It is also difficult for the time indicator to accurately recognize an exposure time to a cooling environment.
In consideration of the above-mentioned circumstances, it is preferable that the critical temperature indicator has an actuation mechanism capable of checking accuracy of actuation from a use time to a termination time to recognize a management status of a storage state according to a time lapse and a critical temperature from a release time of the product.
In addition, it is preferable to provide a simple structure that can be easily used and applied to small frozen and chilled products, and enables mass production.
In order to solve the above-mentioned problems, a strip indicator used in validation of an injection sterilization process is further advances to enable mass production and commercialization to be applied to foods safety management.